Class: RDoc::Markup::AttributeManager

Inherits:
Object
  • Object
show all
Defined in:
lib/rdoc/markup/attribute_manager.rb

Overview

Manages changes of attributes in a block of text

Constant Summary collapse

NULL =

The NUL character

"\000".freeze
A_PROTECT =

– We work by substituting non-printing characters in to the text. For now I'm assuming that I can substitute a character in the range 0..8 for a 7 bit character without damaging the encoded string, but this might be optimistic ++

004
PROTECT_ATTR =

Special mask character to prevent inline markup handling

A_PROTECT.chr

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initializeAttributeManager

Creates a new attribute manager that understands bold, emphasized and teletype text.


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# File 'lib/rdoc/markup/attribute_manager.rb', line 64

def initialize
  @html_tags = {}
  @matching_word_pairs = {}
  @protectable = %w[<]
  @special = []
  @word_pair_map = {}
  @attributes = RDoc::Markup::Attributes.new

  add_word_pair "*", "*", :BOLD
  add_word_pair "_", "_", :EM
  add_word_pair "+", "+", :TT

  add_html "em", :EM
  add_html "i",  :EM
  add_html "b",  :BOLD
  add_html "tt",   :TT
  add_html "code", :TT
end

Instance Attribute Details

#attributesObject (readonly)

The attributes enabled for this markup object.


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# File 'lib/rdoc/markup/attribute_manager.rb', line 28

def attributes
  @attributes
end

#html_tagsObject (readonly)

This maps HTML tags to the corresponding attribute char


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# File 'lib/rdoc/markup/attribute_manager.rb', line 46

def html_tags
  @html_tags
end

#matching_word_pairsObject (readonly)

This maps delimiters that occur around words (such as bold or tt) where the start and end delimiters and the same. This lets us optimize the regexp


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# File 'lib/rdoc/markup/attribute_manager.rb', line 35

def matching_word_pairs
  @matching_word_pairs
end

#protectableObject (readonly)

A \ in front of a character that would normally be processed turns off processing. We do this by turning < into <#PROTECT


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# File 'lib/rdoc/markup/attribute_manager.rb', line 52

def protectable
  @protectable
end

#specialObject (readonly)

And this maps special sequences to a name. A special sequence is something like a WikiWord


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# File 'lib/rdoc/markup/attribute_manager.rb', line 58

def special
  @special
end

#word_pair_mapObject (readonly)

And this is used when the delimiters aren't the same. In this case the hash maps a pattern to the attribute character


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# File 'lib/rdoc/markup/attribute_manager.rb', line 41

def word_pair_map
  @word_pair_map
end

Instance Method Details

#add_html(tag, name) ⇒ Object

Adds a markup class with name for words surrounded by HTML tag tag. To process emphasis tags:

am.add_html 'em', :EM

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# File 'lib/rdoc/markup/attribute_manager.rb', line 230

def add_html(tag, name)
  @html_tags[tag.downcase] = @attributes.bitmap_for name
end

#add_special(pattern, name) ⇒ Object

Adds a special handler for pattern with name. A simple URL handler would be:

@am.add_special(/((https?:)\S+\w)/, :HYPERLINK)

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# File 'lib/rdoc/markup/attribute_manager.rb', line 240

def add_special pattern, name
  @special << [pattern, @attributes.bitmap_for(name)]
end

#add_word_pair(start, stop, name) ⇒ Object

Adds a markup class with name for words wrapped in the start and stop character. To make words wrapped with “*” bold:

am.add_word_pair '*', '*', :BOLD

Raises:

  • (ArgumentError)

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# File 'lib/rdoc/markup/attribute_manager.rb', line 207

def add_word_pair(start, stop, name)
  raise ArgumentError, "Word flags may not start with '<'" if
    start[0,1] == '<'

  bitmap = @attributes.bitmap_for name

  if start == stop then
    @matching_word_pairs[start] = bitmap
  else
    pattern = /(#{Regexp.escape start})(\S+)(#{Regexp.escape stop})/
    @word_pair_map[pattern] = bitmap
  end

  @protectable << start[0,1]
  @protectable.uniq!
end

#attribute(turn_on, turn_off) ⇒ Object

Return an attribute object with the given turn_on and turn_off bits set


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# File 'lib/rdoc/markup/attribute_manager.rb', line 86

def attribute(turn_on, turn_off)
  RDoc::Markup::AttrChanger.new turn_on, turn_off
end

#change_attribute(current, new) ⇒ Object

Changes the current attribute from current to new


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# File 'lib/rdoc/markup/attribute_manager.rb', line 93

def change_attribute current, new
  diff = current ^ new
  attribute(new & diff, current & diff)
end

#changed_attribute_by_name(current_set, new_set) ⇒ Object

Used by the tests to change attributes by name from current_set to new_set


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# File 'lib/rdoc/markup/attribute_manager.rb', line 102

def changed_attribute_by_name current_set, new_set
  current = new = 0
  current_set.each do |name|
    current |= @attributes.bitmap_for(name)
  end

  new_set.each do |name|
    new |= @attributes.bitmap_for(name)
  end

  change_attribute(current, new)
end

#convert_attrs(str, attrs) ⇒ Object

Map attributes like textto the sequence 001002<char>001003<char>, where <char> is a per-attribute specific character


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# File 'lib/rdoc/markup/attribute_manager.rb', line 129

def convert_attrs(str, attrs)
  # first do matching ones
  tags = @matching_word_pairs.keys.join("")

  re = /(^|\W)([#{tags}])([#:\\]?[\w.\/-]+?\S?)\2(\W|$)/

  1 while str.gsub!(re) do
    attr = @matching_word_pairs[$2]
    attrs.set_attrs($`.length + $1.length + $2.length, $3.length, attr)
    $1 + NULL * $2.length + $3 + NULL * $2.length + $4
  end

  # then non-matching
  unless @word_pair_map.empty? then
    @word_pair_map.each do |regexp, attr|
      str.gsub!(regexp) {
        attrs.set_attrs($`.length + $1.length, $2.length, attr)
        NULL * $1.length + $2 + NULL * $3.length
      }
    end
  end
end

#convert_html(str, attrs) ⇒ Object

Converts HTML tags to RDoc attributes


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# File 'lib/rdoc/markup/attribute_manager.rb', line 155

def convert_html(str, attrs)
  tags = @html_tags.keys.join '|'

  1 while str.gsub!(/<(#{tags})>(.*?)<\/\1>/i) {
    attr = @html_tags[$1.downcase]
    html_length = $1.length + 2
    seq = NULL * html_length
    attrs.set_attrs($`.length + html_length, $2.length, attr)
    seq + $2 + seq + NULL
  }
end

#convert_specials(str, attrs) ⇒ Object

Converts special sequences to RDoc attributes


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# File 'lib/rdoc/markup/attribute_manager.rb', line 170

def convert_specials str, attrs
  @special.each do |regexp, attribute|
    str.scan(regexp) do
      capture = $~.size == 1 ? 0 : 1

      s, e = $~.offset capture

      attrs.set_attrs s, e - s, attribute | @attributes.special
    end
  end
end

#copy_string(start_pos, end_pos) ⇒ Object

Copies start_pos to end_pos from the current string


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# File 'lib/rdoc/markup/attribute_manager.rb', line 118

def copy_string(start_pos, end_pos)
  res = @str[start_pos...end_pos]
  res.gsub!(/\000/, '')
  res
end

#display_attributesObject

Debug method that prints a string along with its attributes


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# File 'lib/rdoc/markup/attribute_manager.rb', line 266

def display_attributes
  puts
  puts @str.tr(NULL, "!")
  bit = 1
  16.times do |bno|
    line = ""
    @str.length.times do |i|
      if (@attrs[i] & bit) == 0
        line << " "
      else
        if bno.zero?
          line << "S"
        else
          line << ("%d" % (bno+1))
        end
      end
    end
    puts(line) unless line =~ /^ *$/
    bit <<= 1
  end
end

#flow(str) ⇒ Object

Processes str converting attributes, HTML and specials


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# File 'lib/rdoc/markup/attribute_manager.rb', line 247

def flow str
  @str = str

  mask_protected_sequences

  @attrs = RDoc::Markup::AttrSpan.new @str.length

  convert_attrs    @str, @attrs
  convert_html     @str, @attrs
  convert_specials @str, @attrs

  unmask_protected_sequences

  split_into_flow
end

#mask_protected_sequencesObject

Escapes special sequences of text to prevent conversion to RDoc


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# File 'lib/rdoc/markup/attribute_manager.rb', line 185

def mask_protected_sequences
  # protect __send__, __FILE__, etc.
  @str.gsub!(/__([a-z]+)__/i,
    "_#{PROTECT_ATTR}_#{PROTECT_ATTR}\\1_#{PROTECT_ATTR}_#{PROTECT_ATTR}")
  @str.gsub!(/(\A|[^\\])\\([#{Regexp.escape @protectable.join}])/m,
             "\\1\\2#{PROTECT_ATTR}")
  @str.gsub!(/\\(\\[#{Regexp.escape @protectable.join}])/m, "\\1")
end

#split_into_flowObject

Splits the string into chunks by attribute change


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# File 'lib/rdoc/markup/attribute_manager.rb', line 291

def split_into_flow
  res = []
  current_attr = 0

  str_len = @str.length

  # skip leading invisible text
  i = 0
  i += 1 while i < str_len and @str[i].chr == "\0"
  start_pos = i

  # then scan the string, chunking it on attribute changes
  while i < str_len
    new_attr = @attrs[i]
    if new_attr != current_attr
      if i > start_pos
        res << copy_string(start_pos, i)
        start_pos = i
      end

      res << change_attribute(current_attr, new_attr)
      current_attr = new_attr

      if (current_attr & @attributes.special) != 0 then
        i += 1 while
          i < str_len and (@attrs[i] & @attributes.special) != 0

        res << RDoc::Markup::Special.new(current_attr,
                                         copy_string(start_pos, i))
        start_pos = i
        next
      end
    end

    # move on, skipping any invisible characters
    begin
      i += 1
    end while i < str_len and @str[i].chr == "\0"
  end

  # tidy up trailing text
  if start_pos < str_len
    res << copy_string(start_pos, str_len)
  end

  # and reset to all attributes off
  res << change_attribute(current_attr, 0) if current_attr != 0

  res
end

#unmask_protected_sequencesObject

Unescapes special sequences of text


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# File 'lib/rdoc/markup/attribute_manager.rb', line 197

def unmask_protected_sequences
  @str.gsub!(/(.)#{PROTECT_ATTR}/, "\\1\000")
end